Homemade Blueberry Jam

No ratings yet

Homemade blueberry jam perfect for using on toast, sandwiches, cookies, or other baked goods.

Course Jam

Cuisine American

Prep Time 15

Cook Time 45

Processing Time 10

Total Time 1 10

Servings cups

Calories 36kcal

Place blueberries, sugar, and lemon juice in a large pot.
Stir together so the berries are coated.
Place over medium to medium-low heat. Stir often until the berries have released their juices and the mixture is liquid.
Continue cooking until the mixture comes to a boil. Stir often to prevent scorching.
Cook until the jam reaches the gel stage (see below).
Scoop jam into canning jars leaving a ¼ inch of headspace.
If canning, wipe down rims with a clean cloth. Add lids and rings. Tighten rings just until finger tightened - don't over-tighten.
Process in a water bath canner for 10 minutes (plus additional time for your altitude - see chart for elevation adjustment in the post above the recipe card.

This recipe yields between 5 and 6 cups of jam.

- Use a large pot at least double the size of the amount of ingredients you are using. Once the jam starts to boil, it will foam up and can boil over.

- Keep an eye on your jam while cooking and stir often to ensure it isn't burning.

- Don't be afraid to adjust your heat. I often turn my heat down a bit once my jam begins to boil.

Testing the jam to see if has reached the gel stage:

Test the jam with a thermometer. Jam sets at 220° at sea level. However, the exact temperature will vary, depending on your altitude. You will deduct 2° for every thousand feet above sea level. I'm at about 2000 feet above sea level and my jam sets between 216° - 218°
I usually watch my jam with a thermometer and when it starts getting close to 215° I begin doing the spoon or sheeting test and then the plate test. I don't like to rely on just one method.
The spoon test relies on watching the sheeting or drops as they come off the spoon while it is cooking. When the jam first starts boiling it comes off in drops or thin streams. When the jam has set, the jam will come off the spoon in more of a sheet.
The plate test is putting a small amount of jam onto a co0l plate. Allow to cool for a minute and then run the back of a spoon through the jam. If the jam stays separated, it is done. Tilt the jam - the jam should only have a slight slide

Altitude Adjustments for Canning above 1000 feet in elevation:

1,001-3,000 – increase 5 minutes

3,001-6,000 – increase 10 minutes

6,001-8,000 – increase 15 minutes

8,001-10,000 – increase 20 minutes